Numerical method of forward position solution for 6-3 Stewart platform based on mechanism simplification

To increase the speed of forward position solution for Stewart platform, the classical iterative method based on speed Jacobian was analyzed, and the new method for 6-3 Stewart platform was proposed. 6-3 Stewart platform was simplified as virtual 3-RPS parallel mechanism and its forward position solution was obtained by Newton-Raphson method. The result was solved back to the pose of actual platform. Experimental results on self-designed hydraulic 6-3 Stewart platform system present that, compared with classical method, the new one reduced nearly 50% of iterations and about 85% of time cost for solution. The concept of the new method is clear, mechanism simplification is easy implementing, and the computational cost of forward position solution for simplified 3-RPS parallel mechanism is significantly decreased. The new method is capable for forward position solution in a real-time control with 0.1 ms control cycle.